Analog Devices Inc./Maxim Integrated MAX1278CTC+T

Overview

MAX1278CTC+T from Maxim Integrated is a 12-bit, true-differential, serial-output analog-to-digital converter (ADC) with internal 4.096V reference, 1.8Msps sampling rate, ±1.25 LSB INL, and bipolar input range of ±V_REF/2. It operates from a single +4.75V to +5.25V analog supply and supports 1.8V–V_DD digital logic via dedicated VL pin, enabling direct interfacing with low-voltage microcontrollers in motor control and industrial data acquisition systems.

For engineers reviewing the MAX1278CTC+T datasheet, MAX1278CTC+T pinout, MAX1278CTC+T application, or MAX1278CTC+T equivalent, key selection criteria include its bipolar differential input architecture, SPI/QSPI/MICROWIRE-compatible 3-wire interface, 70dB SINAD at 525kHz, full-power-down current ≤1µA, and TQFN-12 package compatibility with space-constrained embedded signal chains.

Technical Context

The MAX1278CTC+T employs a successive-approximation register (SAR) architecture with an integrated true-differential track-and-hold (T/H), enabling high-fidelity sampling of bipolar signals without external level-shifting. Its internal 4.096V reference remains active in normal and partial power-down modes but is disabled in full power-down mode, requiring ≥2ms recovery before valid conversion.

Conversion is initiated by a falling edge on CNVST, synchronized to SCLK (up to 28.8MHz); 16 clock cycles shift out three leading zeros followed by 12 MSB-first data bits on DOUT. The device supports continuous, burst, and power-managed operation with acquisition time t_ACQ = 104ns and aperture jitter of 30ps - critical for undersampling RF and baseband signals in communications infrastructure.

Key Specifications

Pinout & Package

The MAX1278CTC+T is housed in a 12-pin 3mm × 3mm TQFN package with exposed paddle (EP) internally connected to GND. Pin 1 is AIN−; pin 12 is AIN+. Pins 5 and 11 are no-connect (N.C.). The package supports reflow soldering per JEDEC J-STD-020 and provides low thermal resistance for stable operation at +85°C ambient.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit, high-speed, differential ADC applications.

Compared with ADS8860IDRCT and AD7490BRUZ, the MAX1278CTC+T uniquely combines true-differential bipolar input, integrated 4.096V reference, 1.8Msps throughput, and 1.8V–5V flexible digital I/O - making it optimal for compact, low-power, high-dynamic-range signal acquisition where board space and supply complexity are constrained.

Availability

MAX1278CTC+T is available at Aetrix Electronics and suitable for motor control feedback, industrial data acquisition, and communications baseband applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MAX1278CTC+T includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Maxim Integrated (now part of Analog Devices) designs precision analog, mixed-signal, and power management ICs for industrial, automotive, and communications markets.

The MAX1276/MAX1278 product line targets high-speed, low-power data acquisition in space- and power-constrained systems - emphasizing true-differential input integrity, integrated reference stability, and seamless microcontroller/DSP interfacing.

FAQ

What is the analog input voltage range for the MAX1278CTC+T?

The MAX1278CTC+T features a bipolar true-differential input with a range of –V_REF/2 to +V_REF/2, where V_REF = 4.096V. This yields a total differential input span of ±2.048V (–2.048V to +2.048V), supporting direct connection to AC-coupled sensors or transformer-isolated signals without external level-shifting circuitry. The absolute voltage on AIN+ or AIN− must remain between GND and VDD for reliable operation.

Does the MAX1278CTC+T require an external reference voltage?

No, the MAX1278CTC+T does not require an external reference voltage. It integrates a factory-trimmed 4.096V reference accessible at the REF pin, which drives both the internal capacitive DAC and can serve as a precision reference for external circuitry (up to 2mA source/sink). The reference remains enabled in normal and partial power-down modes but is disabled in full power-down mode, requiring ≥2ms settling time upon exit.

How does the MAX1278CTC+T interface with SPI-compatible microcontrollers?

The MAX1278CTC+T supports all four SPI modes (CPOL/CPHA combinations) via its SCLK, CNVST, and DOUT pins. A falling edge on CNVST initiates conversion; 16 SCLK cycles shift out three leading zeros followed by 12 MSB-first data bits. DOUT transitions t_DOUT after each SCLK rising edge and remains valid for t_DHOLD (4ns), ensuring robust timing margin for standard SPI peripherals without custom bit-banging.

What power-saving modes does the MAX1278CTC+T support, and how are they entered?

The MAX1278CTC+T supports partial power-down (2mA IDD) and full power-down (≤1µA IDD). Partial mode is entered by pulling CNVST high after the 3rd but before the 14th SCLK rising edge; full mode requires executing the partial power-down sequence twice. In full mode, the internal reference is disabled, necessitating ≥2ms recovery before valid conversions resume. Both modes retain register state and require no reinitialization.

Is the MAX1278CTC+T pin-compatible with other devices in the MAX1276/MAX1278 family?

Yes, the MAX1278CTC+T shares identical pinout, package (12-pin TQFN), and electrical interface with the MAX1276CTC+T and all ETC-grade variants (e.g., MAX1278ETC+T). The only functional difference is input polarity: MAX1278CTC+T supports bipolar differential input (±V_REF/2), whereas MAX1276CTC+T supports unipolar input (0 to V_REF). No PCB changes are needed when substituting within this family for compatible signal ranges.